Electromagnetic miniature relay



April 5, 1966 J. FISCHER ET 3,244,834

ELECTROMAGNETIC MINIATURE RELAY Filed Feb. 6, 1961 Fig. i

April 5, 1966 s ETAL 3,244,834

ELECTROMAGNETIC MINIATURE RELAY Filed F'eb. 6, 1961 Z Sheets-Sheet 2 United States Patent Filed Feb. 6, 1961, Ser. No. 87,187 Claims priority, 'application Germany, Feb. 26, 1960,

2 Claims. (a. 200-87) This invention is concerned with an electromagnetic miniature relay which satisfies the requirements posed in the construction of electrical miniature switching devices calling for smallest dimensions of structural elements which shall in extreme cases be adapted for direct soldering to the Wiring of a switching device.

The object of the invention is to provide a relay which is particularly suitable for the above indicated purpose and which has despite its small size relatively high ener- 'gization sensitivity. The relay shall be operable regardless of the position in which it is placed and shall be substantially shockproof. It shall also have a useful life corresponding in length to the life of the remaining structural elements of the switching device in which it is used. This means that the maximum number of switching operations of the contact means of the relay shall be as great as possible.

The present invention shows a Way for solving the problems, arising in connection with these requirements, by means of a miniature relay comprising an armature which is movable within a solenoid. In accordance with the invention, the solenoid is surrounded by a sleeve-like soft iron jacket and is for the greater part of its length provided with a soft iron core cooperating with a bolt like armature which is axially movable therein without friction, such armature being, at the end facing away from the working air gap, fastened to a double spring acting as a parallel guide, and the double spring as well as the contact means cooperating therewith are disposed within a hermetically sealed chamber. The structure according to the invention .oifers particular advantages since the magnetic circuit can be made substantially free of a stray field, thus making it possible to use an armature with small mass and consequently very slight sensitivity to impacts and shocks. The placement of the contact means within a hermetically sealed chamber results in the advantage of providing for a very great number of switching operations and also permits the use of any desired and suitable contact material.

The contact arrangement comprises advantageously a centrally disposed contact, for alternate engagement with cooperating contacts, responsive to actuation thereof by the double spring, which is provided with a bracket controlled by the armature. The working air gap is adjusted by positional adjustment of the soft iron core which is for this purpose provided with a screw thread and held in adjusted position by means of .a magnetically conductive closure or end plate which is connected therewith. The sleeve-like soft iron jacket is suitably held in position on the casing forming the contact chamber, by clamping it thereto at a number of points.

It may be of advantage in given cases to arrange the relay upon a glasssmetal socket.

The pole face of the soft iron core and that of the armature are made cone shaped in order to obtain optimum attraction power.

An embodiment of the invention will now be described with reference to the accompanying drawing, in which FIG. 1 is a part sectional view of the miniature relay on a very much enlarged scale; and

FIG. 2 shows merely the socket with the contact means and armature arranged thereon.

3,244,834 Patented Apr. 5, 1966 As shown in FIG. 1, the relay comprises the solenoid having the coil 4 which is provided with a sleeve-like soft iron jacket 8 and having for the greater part of its length a soft iron core 9, dis-posed within a tube 5 made of a nonmagnetic material, the core 9 cooperating with a bolt-shaped armature 10 which is without friction axially movable Within the tube 5 and fastened at its end, facing away from the working air gap 12, to a double spring 18 acting as a parallel guide. Upon energiz-ation of the relay, the double spring guides the motion of the armature within the solenoid tube 5 out of engagement with the inner wall thereof.

The working air gap 12 is adjusted :by rotation of the core 9 relative to the magnetically conductive closure end plate 7 to which it is screw connected at 9b, and the ad justed position of the core is fixed by bonding it to the end plate and to the non-magnetic tube 5 by soldering. The adjustability of the Working air gap permits equalization or compensation of manufacturing tolerances of the magnetic system and of the contact set employed. Moreover, the attraction index can thereby be adjusted in simple manner.

The sleeve-like soft iron jacket 8 serves for guiding the magnetic flux, which is indicated by dot-dash lines, and also for mechanically protecting the winding of the solenoid coil 4. The soft iron jacket 8 is fastened to the casing 6, which contains the contact means, by clamping it thereto at points such as indicated at 23. In order to obtain optimum energization or attraction power for the armature it), the pole face of the latter as well as that of the soft iron core are formed cone shaped in matching manner, as indicated at 9a and 10a.

The terminal wires for the solenoid coil 4 are placed into recesses (not shown) formed in the soft iron end plate 7 and are soldered to the ends of the coil Winding which extend therefrom.

FIG. 2 shows the contact arrangement of the relay which is together with the double spring 18 disposed in the contact chamber 6a of FIG. 1. The armature 1d is connected with the socket pin 17 through the medium of the wire 19 and the double spring 18, such connection being effected by spot welding at the points indicated by black dots. The socket pin 17 acts thereby as a fixed base for the up and down motion of the double spring 18 occurring responsive to the motion of the armature. The action results in a parallel guiding of the armature 10, thus assuring a frictionless motion thereof within the range of the armature stroke. The double spring 13 serves at the same time as a current lead for the central contact 20 carried by the wire 19. The cooperating contacts 22 extend respectively from the socket pins 21 and 2d. The contact arrangement which is thus fastened on the socket 2 is upon assembly introduced into the casing 6 (FIG. 1) and the socket is thereupon soldered or welded to the casing. The socket 2 forms in this manner a closure at the end of the relay which is opposite to the end plate 7 (FIG. 1). Soldering tabs may be provided in place of the socket pins so as to facilitate direct wiring of the relay.

The sealing and insulation means of the parts disposed in the hermetically sealed chamber are preferably made of inorganic material.

The extremely small dimensions of the individual structural parts make it possible to produce such a miniature relay with a length of about 30 millimeters and a diameter of about 6 millimeters, with the terminals for the winding of the energizing coil and for the contact arrangement extending respectively from the opposite ends of the structure.

Changes may be made within the scope and spirit of the appended claims which define what is believed to be new and desired to have protected by Letters Patent.

We claim:

1. A highly shockproof and operational highly sensitive electromagnetic miniature relay, comprising a solenoid having a coil surrounded by a soft iron sleeve and having a soft iron core extending over the greater part of the length thereof, a cylindrical armature extending into said solenoid for magnetic cooperation With said core, the inner end of said armature being normally separated from the end of said core by an air gap, a device for mounting said armature for frictionless longitudinal motion within said solenoid, said device comprising a pair of longitudinally spaced spring members, of annular configuration, extending transversely to the direction of movement of said armature, a pair of spaced oppositely disposed longitudinally extending members operat-ively connecting said spring members and forming a parallel guide for said armature, one of said spaced members being mounted in fixed relation with respect to said coil and forming a support for said spring members, means (for connecting the outer end of said armature to the other of said spaced members, a first contact operatively connected to said last-mentioned spaced member [or cooperation With relatively fixedly disposed second contact means, said second contact means extending through the adjacent annular spring member, and said first rnentioned contact means extending radially inwardly from the 44 spaced member with which it is associated and a casing vforming a hermetically sealed contact chamber for enclosing said guide and said contact means.

'2. A relay as defined in claim 1, wherein said spring members are disposed concentrically with respect tothe longitudinal axis of said armature, said means for connecting the latter to the associated spaced member extend: in g radially inwardly.

References Cited by the Examiner UNITED STATES PATENTS 1,875,765 9/1932 Scherbius 200--87 2,391,444 12/1945 Bur-ch 200-87 2,415,448 2/1947 Stilwell 311-191 2,425,038 8/1947 Lear 200 111 2,487, 72 11/1949v Raclcley 200-87 2,540,185 2/1951 Brown 200-411 2,714,141 7/1955 Urey r 1 200-111 2,868,922 1/1959 Leonard 200-87 2,908,780 10/1959 Walters 200-144 2,935,584 5/1960 Wcichardt 200-87 BERNARD A. GILH-EANY, Primary Examiner.

MAX L. LEVY, Examiner. 

1. A HIGHLY SHOCKPROOF AND OPERATIONAL HIGHLY SENSITIVE ELECTROMAGNETIC MINIATURE RELAY, COMPRISING A SOLENOID HAVING A COIL SURROUNDED BY A SOFT IRON SLEEVE AND HAVING A SOFT IRON CORE EXTENDING OVER THE GREATER PART OF THE LENGTH THEREOF, A CYLINDRICAL ARMATURE EXTENDING INTO SAID SOLENOID FOR MAGNETIC COOPERATION WITH SAID CORE, THE INNER END OF SAID ARMATURE BEING NORMALLY SEPARATED FROM THE END OF SAID CORE BY AN AIR GAP, A DEVICE FOR MOUNTING SAID ARMATURE FOR FRICTIONLESS LONGITUDINAL MOTION WITHIN SAID SOLENOID, SAID DEVICE COMPRISING A PAIR OF LONGITUDINALLY SPACED SPRING MEMBERS, OF ANNULAR CONFIGURATION, EXTENDING TRANSVERSELY TO THE DIRECTION OF MOVEMENT OF SAID ARMATURE, A PAIR OF SPACED OPPOSITELY DISPOSED LONGITUDINALLY EXTENDING MEMBERS OPERATIVELY CONNECTING SAID SPRING MEMBERS AND FORMING A PARALLEL GUIDE FOR SAID ARMATURE, ONE OF SAID SPACED MEMBERS BEING MOUNTED IN FIXED RELATION WITH RESPECT TO SAID COIL AND FORMING A SUPPORT FOR SAID SPRING MEMBERS, MEANS FOR CONNECTING THE OUTER END OF SAID ARMATURE TO THE OTHER OF SAID SPACED MEMBERS, A FIRST CONTACT OPERATIVELY CONNECTED TO SAID LAST-MENTIONED SPACED MEMBER FOR COOPERATION WITH RELATIVELY FIXEDLY DISPOSED SECOND CONTACT MEANS, SAID SECOND CONTACT MEANS EXTENDING THROUGH THE ADJACENT ANNULAR SPRING MEMBER, AND SAID FIRST-MENTIONED CONTACT MEANS EXTENDING RADIALLY INWARDLY FROM THE SPACED MEMBER WITH WHICH IT IS ASSOCIATED AND A CASING FORMING A HERMETICALLY SEALED CONTACT CHAMBER FOR ENCLOSING SAID GUIDE AND SAID CONTACT MEANS. 